What Ground Control Changes—and What It Does Not
March 10, 2026
Ground control points are surveyed reference marks used to tie a photogrammetric or LiDAR dataset to a known coordinate system with stated accuracy, rather than an internally consistent but arbitrarily placed one.
Adding control generally improves absolute positional accuracy — where a feature sits relative to the real world — more than it improves relative accuracy between two nearby points, which is driven mainly by image overlap, geometry and processing.
Ground control cannot compensate for insufficient overlap, poor lighting or an under-scoped flight plan. It also is not always necessary: a relative measurement for a repair bid may not need survey-grade absolute accuracy at all.
The scoping conversation should identify whether the intended use needs absolute positioning, relative measurement, or both, before deciding whether control is worth the added time and cost.
Professional boundaries
- Legal boundary and property line determinations require a licensed land surveyor.
- Final tax positions, asset lives and depreciation treatment require a qualified tax professional.
- Structural, mechanical and other engineering conclusions require a licensed engineer.
- Official valuations and appraisals require a licensed appraiser.
- Thermal imagery indicates apparent anomalies only and is not a diagnosis.
- Legal opinions, causation findings and expert testimony require qualified counsel and retained experts.
Start with the decision you need to make.
Tell us the property and the decision. You get a written scope with an exact price before anything is scheduled.